1. Field of the Invention
The present invention generally relates to a cooling fan and, more particularly, to a blower fan.
2. Description of the Related Art
Conventional cooling fans include axial-flow fans and blower fans. The axial-flow fan has an axial air inlet and an axial air outlet opposite to the axial air inlet. Air can be drawn into the fan via the axial air inlet and then expelled from the fan via the axial air outlet, achieving a desired cooling effect. The blower fan has an axial air inlet in an axial direction and a radial air outlet in a radial direction of the fan. Air can be drawn into the fan via the axial air inlet and then expelled from the fan via the radial air outlet for cooling purposes.
Since the axial-flow fan expels air only in the axial direction, the axial-flow fan must be mounted on the top of an electronic device to be cooled, such as a Central Processing Unit (CPU) of a computer. As a result, the height of the electronic device cannot be reduced.
In addition, since the blower fan is able to expel air via the radial air outlet, the blower fan does not have to be mounted on the top of the heat source. Advantageously, the blower fan can be installed in any kind of miniaturized electronic device with limited interior space. However, when the blower fan is installed in an electronic device, foreign debris (such as dust or water) may intrude into the fan via its axial air inlet, resulting in damage to the fan.
In light of this problem, Taiwan Patent No. 1330224 discloses a blower fan 9 as shown in FIG. 1. The blower fan includes a fan frame 91 having an axial air inlet 911 and a radial air outlet 912. Fan frame 91 receives an impeller 92 and a motor that is used to drive impeller 92 to rotate. When the motor drives impeller 92 to rotate, air can be drawn into the fan via axial air inlet 911 and expelled from the fan via radial air outlet 912, achieving a desired cooling effect.
In blower fan 9, a barrier 93 is arranged along a periphery of axial air inlet 911. In this arrangement, although barrier 93 is able to prevent the foreign debris or liquid from intruding into fan 9 in a lateral direction of the axial air inlet 911, the foreign debris or liquid from above fan 9 may still intrude into fan 9 via axial air inlet 911, resulting in damage to fan 9. Furthermore, when a user installs fan 9 into an electronic device by his/her hands, the user is liable to accidentally touch impeller 92 through axial air inlet 911, resulting in damage to fan 9 and causing inconvenience during the installation of fan 9. In addition, the user's fingers may be hurt when accidentally touching impeller 92 during the rotation of impeller 92. Disadvantageously, safety of fan 9 is poor.